Weft straightening apparatus



April 9, 1940. -r. M. BERRY WSFT STRAIGHTENING APPARATUS Filed Aug. 27, 1938 2 Sheets-Sheet l Inverwtor: Theodore M. Berr 's Attorn ey.

April 9, 1940.

1'. M. BERRY 2. 6.893

WIF'I s'mneu'rsume APPARATUS Filed Aug. 27, 1938 2 Sheets-Sheet 2 Inventor:

Theodore M.- Berry,

'19 6) by H8447 i s Att orn ey.-

Patented Apr. 9, 1940 WEF'I' STRAI'GHTENING APPARATUS Theodore M. Berry;v Schenectady, N. Y., assignor to General. Electriccompany, a corporation of New York Application August 27, 1938, Serial No. 227,148

12: Claims.

My invention relates to the manufacture of through a slot 6 and by dotted lines at each side woven material, such as woven fabrics, where it is desirable that the finished material shall be straight, that is, that there shall not be any skew or bow in the weft elements thereof.

The object of my invention is to provide improved apparatus for straightening'woven material whether the lack of straightness therein is due to the material being either skewed or bowed or being both skewed and bowed and whether the lack of straightness exists throughout the entire width of the material or is present in only' fa certain portion thereof.

My invention will be better understood from the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

Referringto the drawings, Fig. 1 is a perspective view of apparatus embodying my invention; Fig. 2 is a detail of a portion thereof; Fig. 3 shows one of the optical systems forming a part thereof; Fig. 4 shows a portion of the material requiring straightening together with a part of the one optical system; and Fig. 5 is a circuit diagram of the apparatus.

In the drawings the strip of material to be straightened is shown at i arranged to be drawn along longitudinally by being wrapped around the roll 2 having driving means, not shown, the strip as it approaches the roll passing over the idler rolls 3 and 4. As the material is drawn along, I project therethrough a transversely moving narrow beam of light which: is successively intercepted by the weft members of the material and the resulting interruption of this beam of light by the weft members produces impulses the frequency of which is used to detect any lack of straightness in the weft members, such as may result from the presence of skew or bow in the material, and to control mechanism for correct ing such lack of straightness.

For thus projecting the light beam through the material I have provided mechanism similar to that shown in the La Pierre Patent 2,106,611. L As shown in Fig. 2, the apparatus comprises the ro tatablc disc 5 having therein a plurality of equally spaced radial slots 6, the disc being directly mounted on the shaft of the electric motor 7:. Adjacent to the motor is the optical system 8 which comprises the light source 9, such asa small electric lamp, the light from which is focussed by the condensing lens ill and the cylindrical lens Ii into a narrow beam on the disc 5 which disc} it will be understood, is arranged close beneath the strip i. Above the strip and in alignment with the aforesaid lenses is the condensing lens l2 and the photo-electric device 13, such for example as a photo-electric tube. As" shown more clearly in Fig. 4 the narrow light beam re resented at 15 by a single black line as seen thereof, extends transversely of the strip and the warp members thereof. As a result of the rotation of the disc 5 and the longitudinal movement of the strip, that portion of the light beam which passes through the successive slots 8 in the disc as it rotates will move in a path relative to the strip which extends diagonally thereof as shown by the dotted rectangle Hi. It will readily be seen that if the cloth is straight. that is if the weft members extend at right angles to the warp members, the number of interruptions of the light beam will be of a certain value. If, however, the weft members are inclined in one direction, such for example as shown in Fig. 4, the number of interruptions of the light beam due to the passage of each slot 6 will be decreased. Conversely, if the weft members are inclined in the opposite direction the number of interruptions will be increased. Thus, if the material is straight the frequency output of the photoelectric device I3 will have a certain definite value but if there is skew or how in the material the frequency of the output will be increased or decreased in accordance with the character of the skew or bow and also the amount of increase or decrease in the frequency will be a measure of the amount of the skew or bow.

To provide a basis of comparison of the variable output frequency of the device [3, I cause the weft elements of the material successively to interrupt another light beam which is stationary. This second light beam is produced by a suitable source such as a small electric lamp i8 whose light is focused by means of the condensing lens l9 and the cylindrical lens 20 into a narrow beam extending transversely of the warp elements of the strip like that produced by the optical system 8. On the opposite side of the strip the light is focused by the condensing lens 2! onto the photoelectric device 22 which may be a photoelectric tubc like the device I 3. As the strip l is drawn along, the output of the device 22 will have a frequency corresponding with the number of weft elements passing a fixed point. By the apparatus to be described later, any lack of straightness in the strip of material is detected by a comparison of the output frequency of the devices i3 and 22. The presence of skew or bow in the strip not only is detected but mechanism for correcting such a condition is controlled.

In accordance with one feature of my invention the optical system 8 is caused to reciprocate back and forth continually across the strip whereby various transverse portions thereof are examined for any lack of straightness. For this purpose I have provided two transversely movable carriages one shown at 24 below the strip arranged to slide on the stationary transverse guides 25 and the other shown at 26 above the strip arranged to slide housing 3! which contains the amplifier for the photoelectric device. These two carriages arecaused to travel back and forth across the strip in unison by means of the two shafts 33 and 34 each having reverse threads or grooves cut there in which are engaged by followers carried by the respective carriages. The shafts 33 and 34 are geared together by the spur gearing 35 and are arranged to be driven from the drum 2 by means of the countershaft 36 and suitable bevel gearing at the ends thereof. Thus, as the drum rotates to draw along the strip, the two carriages are caused to travel back and forth in unison across the strip with a speed which is proportional to the rate of movement of the strip. While the carriages thus travel across the strip, the apparatus automatically detects any skew or how that may exist in the strip as a whole or in any local transverse portion thereof.

In accordance with another feature of my invention I have provided means automatically to remove any such bow or skew that may be detected in the strip. I do this by providing means for resisting the forward movement of the strip at the proper transverse portions thereof in accordance with the amount of skew or bow to be corrected. Mounted in the upper carriage 2| is the caster 38 having the rubber roller 39 adapted I to squeeze the material against the lower plate 28 wheel 44. This wheel is threaded on the screw 45 engaging the spring and is retained against longitudinal movement in the carriage by the spline and pin connection 46. Thus, if the motor shaft turns in one direction in response to the detection of skew or bow in the material, the spring 4| will be compressed to increase the drag imposed upon the forward movement of the material, Conversely, if the motor shaft turns in the opposite direction, the drag imposed on the material will be decreased or eliminated.

The apparatus by which the frequency output of the two photoelectric devices l3 and 22 are compared, represented diagrammatically by Fig. 5, is like that disclosed by Fig. 6 in the abovementioned La Pierre Patent 2,106,611 in that I employ a main capacitor 54 which is given a charge of one polarity or the other from the auxiliary capacitors 63 and 65 in accordance with the relative frequency output of the two photoelectric devices. The auxiliary capacitors are kept charged from the source of direct current supply 6!. Inasmuch as the apparatus which I employ for thus charging the capacitor 64 and which I have shown in Fig. 5 is identical with that disclosed in the aforesaid patent, I shall omit a detailed description of such apparatus herein. B the apparatus which I shall now describe. the direction of rotation of the motor 42 is controlled by the polarity of the charge on the capacitor 64 and the speed of rotation of said motor is controlled by the amount of the charge on said capacitor. The motor is provided with the two opposed field windings "HI and H which are included respectively in the anode circuits of the vapor electric discharge devices 12 and 13,

which circuits are supplied with alternating current from the secondary 14 of the transformer 15, the armature of the motor being connected in series therewith. The primary of the transformer may-be supplied from any suitable source. The grid circuits of the discharge devices 12 and 13 are supplied from across the resistors 68, which with the resistor 66 form a voltage divider across the capacitor 64. The grids are also supplied with phase-displaced voltage obtained from the secondary winding Hi of transformer 15 through the phase displacing network 11 which is of well known construction.

Preferably the speed of the motor 42 is substantially proportional to the tangent of the angle of inclination of the weft elements of the strip from their normal perpendicular relation. Then since the force tending to retard any portion of the strip bears a direct relation to the pressure exerted thereon by the roller, the combinationof the motion of the roller across the strip and the rotation of the motor 42 will cause a correcting force to be applied to the strip which is proportional to the displacement of the weft elements away from the straight or normal position thereof.

Referring to Fig. 4, it will be seen that with the material of the strip skewed as therein shown and moving to the right, if the scanning apparatus carried by the carriages is moving upward as viewed in that figure, the motor 42 should operate in'the direction to increase the pressure applied by the roller 39. Conversely if the scanning apparatus is moving downward, the motor should operate in the direction to decrease the applied pressure. For this reason I reverse the direction of rotation' of the motor at each end of the path of travel of the carriages. A reversing switch represented at in the armature circuit of motor 42 is supported by the upper housing 3| and is.

moved to one position or the other by the projecting arm Bl thereof engaging one or the other of the two fixed stops 82, 83 which are properly positioned with respect to the path of the movement of the carriages.

In the operation of the apparatus the strip l is drawn along in the direction indicated by the arrow by means of the driving roll 2. Through their connection with the driving roll the two carriages travel simultaneously back and forth across the strip thereby scanning all parts thereof between its two edges. With the strip moving at a constant speed and having straight weft elements and with a constant speed of rotation of the disk 6 the interruption of the light beam of the optical system 8 and hence the output frequency of the photo-electric device l3 will have a fixed and definite value. If, however, the strip is skewed or bowed the frequency will be greater or less than before depending upon the direction of the inclination of the weft elements. Also the amount of change in the frequency will depend upon the degree of the inclination. The output frequency of the device 22 remains fixed since it depends only upon the speed of the strip.

the amount of such charge is a measure of the amount of the inclination.

The motor 42 by which a variable drag is applied to oppose the movement of a portion of the strip is controlled by the discharge devices 12 and 13 in accordance with the charge on the main capacitor. Thus, if the capacitor has a charge of one polarity the device 12 will pass more current than the device 13 and the motor will run in one direction; likewise, if the capacitor charge has the opposite polarity the device 13 will pass the more current and the motor will run in the other direction. Moreover, the motor speed in each case will depend upon the amount of the charge on the main capacitor. Since the carriages carrying the scanning apparatus and the motor actuated pressure wheel for straightening the material are carried continually back and forth across the strip it will be seen that by the apparatus which I have devised all portions lying between the two edges or selvages of the strip are scanned and subjected to whatever corrective effect is necessary to remove any skew or bow that may be present therein.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, means for moving a strip of woven material longitudinally and means arranged to cooperate therewith for detecting any lack of straightness in the weft members of said material comprising fixed means for producing impulses in response to the passage thereby of the weft elements of the material, transversely movable means for producing impulses in response to the passage thereby of the weft elements and a device operable in response to a difference in the frequencies of said impulses.

2. In combination, means for moving a strip of woven material longitudinally, fixed means for producing an impulse frequency in response to the passage thereby of the weft elements of the material, means movable transversely of the strip for producing an impulse frequency in response to the passage thereby of said weft elements and means responsive to a difierence in said impulse frequencies for straightening the weft elements of said material.

3. In combination, means for moving a strip of woven material longitudinally, means for illuminating portions of said strip, a plurality of photoelectric devices arranged each to receive a narrow beam of light from one of said illuminated portions and rendered pulsating by the weft members of the material, one of said beams being stationary, means for moving the other of said beams transversely of the strip simultaneously with the longitudinal movement thereof and straightening means responsive to a dinerence in the output frequencies of said devices.

4. In combination, means for moving a strip of woven material longitudinally, means for illuminating said strip, a plurality of photoelectric devices each arranged to receive light in a narrow beam from said strip whereby the passage of the successive weft elements of the material produce impulses in the received light, means for holding one of said devices in a fixed position, means for moving another of said devices transversely of said strip and means movable transversely of the strip for straightening the weft elements thereof in response to a difference in the output frequencies of said devices.

5. In combination, means for moving a strip of woven material longitudinally, means for de-- tecting a lack of straightness in the Weft elements of said material successively at various different transverse portions thereof and straightening means for said elements operable with a variable effect at said portions of the material in accordance with the lack of straightness detected thereat.

6. In combination, means for moving a strip of woven material longitudinally, means movable across said strip for detecting a lack of straightness of the weft elements therein and straightening means for said elements operable with a variable eifect at different transverse portions of the strip in accordance with the lack of strai htness detected at said portions.

7. In combination, means for moving a strip of woven material longitudinally, means movable across said strip for detecting a lack of straightness of the weft elements thereof and straightening means for said elements movable across said strip and constructed to produce a variable effect at different transverse portions thereof in response to the amount of the detect-ed lack of straightness at said portions.

8. In combination, a drum arranged to engage and move a strip of woven material longitudinally and straightening means therefor comprising means for impeding the longitudinal movement of the strip at one point thereof, means for causing said point to move across the strip and means for varying the effect of said impeding means.

9. In combination, a drum arranged to engage and move a strip of woven material longitudinally and straightening means for the weft elements thereof comprising a plate over which said strip moves, means movable transversely of the strip for pressing a portion of the strip against the plate to impede its movement and means for varying the pressure exerted by said pressing means.

10. In combination, a drum arranged to engage and move a strip of woven material longitudinally and straightening means for the weft elements thereof comprising a plate over which said strip moves, means for moving said plate transversely of the strip and means movable with said plate for variably pressing the material against it.

11. In combination, a drum arranged to engage and move a strip of woven material longitudinally, means for detecting a lack of straightness in the weft elements of the material at a point which moves across the strip, means for impeding the longitudinal movement of the strip at a part thereof adjacent said point and means responsive to said detecting means for varying said impeding means.

12. In combination, a drum arranged to engage and move a strip of woven material longitudinally, means including a photoelectric device movable across said strip for detecting a lack of straightness of the weft elements in the successive transverse portions of the strip, a plate on one side of the strip, a roller on the other side thereof movable with and arranged adjacent to said device and means responsive to said detecting means for variably pressing the strip between the plate and the roller.

THEODORE M. BERRY. 

